Specification Part 3 - Road & Bridge Works - Urban Administration ...

Rivets shall be healed uniformly to a "light cherry red" colour between 650 degrees Celsius to
700 degrees Celsius for hydraulic riveting and "orange colour" for pneumatic riveting of mild steel rivets
and shall be red hot from head to the point when inserted and shall be upset in its entire length so as to
fill the hole as completely as possible when hot. Rivets, after being heated and before being inserted in
the hole shall be made free from scale by striking the hot rivet on a hard surface.
Wherever possible, the rivets shall be machine driven, preferably by direct acting riveters. The
driving pres sure shall be maintained on the rivets for a short time after the upsetting is completed. High
tensile steel rivets shall be heated upto 1100 degrees Celsius. Any rivet whose point is heated more
than prescribed, shall not be driven.
Where flush surface is required, any projecting metal shall be chipped or ground off.
Before riveting is commenced, all work shall be properly bolted up so that the various sections
and plates are in close contact throughout Drifts shall only be used for drawing the work into position
and shall not be used to such an extent as to distort the holes. Drifts of a larger size than the nominal
diameter of the hole shall not be used. The riveting s hall be done by hydraulic or pneumatic machine
unless otherwise
specified by the Engineer.
Driven rivets, when s truck sharply on the head by a quarter pound rivet testing hammer, shall
be free from movement and vibrations. Assembled riveted joint surfaces, including those adjacent to the
rivet heads, shall be free from scale, dirt, loose scale, burrs, other foreign materials and defects that
would prevent solid seating of parts.
All loose or burnt rivets and rivets with cracked or badly formed defective heads or with heads
which are unduly eccentric with the shanks, shall be removed and replaced. In removing rivets, the
head shall be sheared off and the rivet punched out so as not to injure the adjacent metal and, if
necessary, they shall be drilled out. Recupping or recaulking shall not be permitted. The parts not
completely riveted in the shop shall be secured by bolts to prevent damage during transport and
handling.
1904.5. Bolts, Nuts and Washers
1904.5.1. Black bolts (black all over) : Black bolts are forged bolts in which the shanks, heads and nuts
do not receive any further treatment except cutting of screw threads. They shall be true to shape and
size and shall have the standard dimensions as shown on the drawings.
1904.5.2. Close tolerance bolts : Close tolerance bolts shall be faced under the head and turned on the
shank.
1904.5.3. Turned barrel bolts : The diameter of the screwed portion of turned barrel bolts shall be 1.5
mm smaller than the diameter of the barrel unless otherwise specified by the Engineer. The diameter of
the bolts as given on the drawing shall be the nominal diameter of the barrel. The length of the barrel
shall be such that it bears fully on all the parts connected. The threaded portion of each bolt shall
project through the nut by at least one thread. Faces of heads and nuts bearing on steel work shall be
machined.
1904.5.4. High strength friction bolts and bolted connections: The general requirement shall be as per
relevant IS specifications mentioned in clause 5.3 of (Fasteners) of IRC24. Unless otherwise specified
by the Engineer, bolted connections of structural joints using high tensile friction grip bolts shall comply
with requirements mentioned in IS:4000.
1904.5.5. Washers : In all cases where the full bearing area of the bolt is to be developed, the bolt shall
be provided with a steel washer under the nut of sufficient thickness to avoid any threaded portion of
the bolt being within the thickness of the parts bolted together and to prevent the nut when screwed up,
from bearing on the bolt.
For close tolerance or turned barrel bolts, steel washers whose faces give a true bearing shall
be provided under the nut. The washer shall have a hole diameter not less than 1.5 mm larger than the
barrel and a thickness of not less than 6 mm so that the nut when screwed up, will not bear on the
shoulder of the bolt.